Offset, zigzag, and staggered key



Mar. 20, 1923. 1,449,341

. G. T. MILLS ET AL OFFSET, ZIGZAG, AND STAGGERED KEY Filed Feb. 27,1922 awuentow 6.727172 719- JHJmar-s' Patented Mar. 2%, i923.

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OFFSET, ZIGZ AG, AND STAGG-ERED KEY.

Application filed February 27, 1922. Serial No. 539,507. a

To all whom it may concern:

Be it known that we, GEORGE T. Mums and JOSEPH H. DEMARs, citizens ofthe United States, residing at Athol and Worcester, respectively, in thecounty of Worcester and State of Massachusetts, have invented certainnew and useful Improvements in Oflset, Zigzag, and Staggered Keys; andwe do declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to whichit appertains to mak and use the same. i

This invention relates to an improved key which is designed forconnecting a machine element such as a pulley, gear, or the like to ashaft, the same being especially, but not necessarily, designed forconnecting the timer gears of an automobile engine to the shafts onwhichthey are mounted.

It has been found after careful study, that a great deal of automobileengine trouble is due to the fact that undue play exists between theintermeshing timing gears. This result is probably due to the fact thatat the time of manufacturing, the parts under consideration are not madeaccurately because of defective workmanship. Poor timing is also causedby the continual wear w to which the gear teeth are subjected.

It is therefore the object of this invention to provide a key which issuch in construction that it will correct the defaults above pointed outand will restore the gears to their original positions, will compensatewear and insure correct relation of the gears and perfect timing of thevalves. These re sults are accomplished by employing a key which is suchin construction that it will advance or retard the operation of thevalves by simply permitting the gear to be moved with respect to theshaft in the proper direction.

Another object of the invention is to provide a key of this class whichis such in construction that it can be substituted for the VVoodrufikeys such as are now commonly employed.

In the accompanying drawings forming a part of this specification and inwhich like numerals are employed to designate like parts throughout thesame:

Figure 1 is an elevational view of the timing gears of a conventionaltype of automobile showing one of these gears connectiad with the crankshaft with my improved rey.

Figure 2 is a sectional view taken substantially on the plane of theline 22 of Fig.1.

Figure 3 is a detail perspective view of the improved key.

In the drawings, A designates the drive gear which is connected with theengine crank shaft B. This gear meshes with a relatively larger timergear C which is keyed or otherwise secured to the tappet shaft D whichserves to actuate the engine valves.

Persons skilled with automobiles, espe cially Fords, will remember thatthe type of keys now employed and commonly known as VVoodrufl keys aresubstantially semicircular in shape and are adapted to be seated inshallow correspondingly shaped keyways formed in the shaft. That is, aportion of the key is to be seated in the groove in this shaft while theremaining portion is received in the co-acting groove or key-way in thegear. Although, it is not necessary,

we prefer to construct our key of the same design as the one abovementioned to enable it to be substituted for the same without requiringany alterations. By referring to the detail view of the key in Fig. 3,it will be seen that the same comprises a semi-circular body 1 which hasopposed fiat sides 2. In accordance with our ideas, the upper half ofthe key is offset laterally as indicated at 3. With this construction,the lower half of the'key is permitted to be seated in the usual curvedgroove or key-way E in the crank shaft whereas the offset portion isreceived in the co-acting key-way F formed in the hub of the small gearA. When placing the key in position and arranging the offset upperportion 3 toward the right, the operation of the valves will be advancedbecause the gear A will be moved around the shaft slightly toward theright. However, if it is. desired to retard the operation of the valves,the key is reversed and the oifset part disposed toward the left. Hence,it will be seen that wear of the gear teeth may be compensated andincorrect timing of the valves rectified.

The manner of restoring the timing gears to their original positions orto enable them to be positioned on the shaft to rectify and correctvalve timing caused by improper workmanship or other reasons has beenmade clear by the foregoing description and drawing. In View of this amore lengthy and detailed description Will be omitted.

Before concluding, it is desired to point out that although the improvedkey has been disclosed as being modeled after a marketed type of key, itis desirable in some instances to vary the shape and size thereof, yetto retain the feature of offsetting a part thereof to accomplish theresult set forth.

We claim:

1. A key having a fiat-faced portion for reception in grooves in a shaftand an element to be mounted thereon, that portion of the key receivedin the groove in said element being laterally offset With respect toGEORGE T. MILLS. JOSEPH H. DEMARS.

